Before installing Rvision, you will need to install the latest version of the devtools package in R.You can install devtools as follows:
install.package("devtools")You can install Rvision as follows:
devtools::install_github("swarm-lab/Rvision")Rvision depends on ROpenCVLite to access OpenCV’s functionalities. If not already installed, ROpenCVLite will be installed first by the above command line. This may take some time as it will download, compile and install OpenCV for you (compilation time will depend on your computer). I suggest going out for a cup of tea or coffee while ROpenCVLite is installing ;-)
library(Rvision)
# Locate sample file
samplePath <- system.file("sample_img", "bunny.png", package = "Rvision")
# Read image file
img1 <- image(samplePath)
img1## C++ object <0x7fc5664df760> of class 'Image' <0x7fc56648b5e0>
plot(img1)dim(img1)## [1] 720 1280 4
nrow(img1)## [1] 720
ncol(img1)## [1] 1280
nchan(img1)## [1] 4
bitdepth(img1)## [1] "8U"
colorspace(img1)## [1] "BGRA"
outfile = tempfile(fileext = ".png")
write.Image(img1, file = outfile)## [1] TRUE
file.exists(outfile)## [1] TRUE
img2 <- changeColorSpace(img1, "GRAY")
plot(img2)img3 <- img2 > 128 # Gray values > 128 are turned to white (255)
# Gray values <= 128 are turned to black (0)
plot(img3)